The Frost Caves biome is a frozen biome which is sayd to be the most dangerous biome in the Soul Forest Dimension. As it comes with 2 different types of snow. Normal Soul Snow and Thick Soul Snow. Naturally some patches of Normal Soul Snow happen to spawn right underneath the top layer of snow which can create quite some dangerous situations in the nether-like generated landscape.
Inside this biome many Ice Towers will be generated which currently don't contain anything but will have mob spawners/chests in the future.
The Frost Caves biome currently holds a few mobs: